N_(S,K,R,M)等值线图所展示的川滇地区强震的前兆图象

The precursor patterns of the strong earthquakes in Sichuan and Yunnan provinces of China shown by N S,K,R,M isograms

充分展示了ＮＳ，Ｋ，Ｒ，Ｍ等值线图的预测效能。这种图定量、直观。利用他捕捉到了一些有效的前兆现象，其中最主要的是：①ＭＳ≥７．０地震前３年震中附近ＭＬ≥３．５地震频数显著增加；②ＭＳ≥７．０地震前１年研究区ＭＬ≥２．０地震频数降半；③ＭＳ≥６．０地震后地震活动数年不衰的地区是未来ＭＳ≥７．０地震发生的可能地点；④孟连—普洱及其附近地区余震中心偏离主震震中逼近未来强震震中；⑤普洱地区地震活动性低，次年发生ＭＳ≥６．０地震的可能性较小。文中用广义地震成核模型对现象①进行了物理解释。

In this paper,the prediction effectiveness of N S,K,R,M isograms are shown.The advantage of this method is quantitative and visual.Some effective precursors are found by using these isograms.The major phenomena are as follows:① the frequency of the M L≥3.5 earthnquakes began to increase markedly three years before the M S≥7.0 earthquakes;② the frequency of the M L≥2.0 earthquakes in the studied area decreased by half one year before the M S≥7.0 earthquakes;③ the coming M S≥7.0 earthquakes will occur where the seismicity does not attenuate for several years after the M S≥6.0 earthquakes;④ the center of the aftershocks diverted from the mainshocks and moved to the epicenter of the coming strong earthquakes in Pure Menglian and the area in the vicinity;⑤ there is lower seismicity in Pure Menglian,so the probability for M S≥6.0 earthquakes is small there. Eventually,the phenomenon ① was explained by using the model of general nucleation of earthquake.